APPLICANT'S DESCRIPTION: The progression of cancer and the experimental reversal of tumorigenicity are accompanied by complex changes in the patterns of gene expression. DNA micro-arrays make it possible to quickly generate large amounts of data for gene expression monitoring, target screening, and many other applications. Understanding the function of individual genes is a challenging objective. Bioanalytical microsystems, such as immunologic and hybridization assays in micro-array format, require using high-density spotting technology that can dispense tiny (nanoliter or picoliter) quantities of solutions containing sufficient biospecific probes onto a given solid support. To achieve this objective, Intelligent Optical Systems (lOS) will develop microspotting arrays that offer millions of features with consistent spot size and spot-to-spot reproducibility, and will enable the rapid mass production of DNA chips. The proposed spotting arrays are extremely versatile. In Phase I, lOS will investigate the feasibility of MEMS-based spotting arrays by testing DNA samples and evaluating the consistency of spotted sample sizes, quantities, spot uniformity, spot density, deposition precision, minimal spot size, and the coefficient of spot-to-spot variation. PROPOSED COMMERCIAL APPLICATION: MEMS-based spotting devices will be used in the fabrication of DNA chips in many industries, such as health care and agriculture, and for food and water testing, and forensic and paternity testing. The commercial potential of this technology is very large, since it will revolutionize the fabrication of biochips, and will find use in environments ranging from clinical laboratories to biotechnology research facilities.